Influência dos Afloramentos Rochosos sobre a Comunidade Lenhosa no Cerrado stricto sensu

Abstract

RESUMOObjetivou-se verificar como os afloramentos rochosos influenciam os padrões ecológicos das espécies lenhosas no cerrado stricto sensu e se existem espécies indicadoras de ambientes. Foram amostradas dez parcelas e registrados todos os indivíduos lenhosos vivos com DAS ≥ 5 cm e também as porcentagens de coberturas de afloramentos rochosos. Para avaliar as relações florísticas, foi empregada uma Análise de Correspondência Retificada (DCA), e utilizou-se a Análise de Espécies Indicadoras (ISA), na determinação das preferências das espécies pelos ambientes. Foram calculados os parâmetros fitossociológicos e realizado um teste t de Student para amostras independentes com algumas variáveis estruturais. A DCA confirmou a existência de dois ambientes e mostrou que a presença dos afloramentos rochosos modifica a composição florística entre eles. A ISA mostrou que existem espécies indicadoras de ambientes. A presença dos afloramentos rochosos alterou o conjunto de espécies de maior Valor de Importância (VI) em cada ambiente, porém não houve diferença significativa entre os parâmetros estruturais avaliados em cada ambiente.Palavras-chave: relação substrato-vegetação, ambientes rupestres, espécies indicadoras. The Influence of Rocky Outcrops on the WoodyCommunity of a Cerrado stricto sensu ABSTRACTThe aim of this study was to verify the presence of environmental indicator species and the influence of rocky outcrops on the ecological patterns of woody plant species in a Cerrado stricto sensu. Ten plots were sampled where information regarding rocky outcrops and all live individuals with DAG ≥ 5 cm were registered. Detrended Correspondence Analysis (DCA) was performed to assess floristic relations, while Indicator Species Analysis (ISA) was used to determine the environmental preferences of species. Phytosociological parameters were calculated, and the Student's t test was conducted for independent samples with some structural variables. The DAG of live individuals confirmed the existence of two environments and showed that the presence of rocky outcrops changes the floristic composition between them. The ISA verified the presence of environmental indicator species. The presence of rocky outcrops changed the group of species presenting higher Importance Value (VI) in each environment; however, no significant differences were found between the structural parameters assessed in each environment.

Influence of Soil Type and Rocky Outcrops on the Species Distribution in a Woody Plant Community at Brazilian Semiarid

“…Haridasan (2000) points out that several species of family Vochysiaceae are aluminum accumulators a trait which, therefore, gives them an adaptive advantage in environments with the presence of exchangeable aluminum. Mota et al (2014), following the same trend of the results obtained in this study, confirmed this hypothesis and indicated that Vochysiaceae and Fabaceae are the most representative families of the Brazilian Cerrado and that, nevertheless Fabaceae, despite having the nitrogen fixation capacity as one of its adaptive advantages for this domain, seems to be more influenced by rocky outcrops than Vochysiaceae.…”

“…Brazilian Cerrado is the world's richest savanna in terms of biodiversity (Silveira, 2010), with 11,000 species of native plants are already cataloged (Klink & Machado, 2005). It ranges through an estimated area of 2,036,448 Km 2 , exclusively in Brazil (IBGE, 2018), covering 23% of the national territory (Ribeiro & Walter, 2008;Mota et al, 2014). Cerrado sensu stricto is found in high elevation reliefs, mainly in deep and well-drained soils, having an herbaceous layer dominated by grasses and a woody layer with diverse heights, varying mainly from three to five meters (Felfili & Fagg, 2007).…”

“…Ribeiro and Walter (2008) determined 11 phytophysiognomic types for the Cerrado biome, distributed between forest, savanic and prairie formations, with Cerrado sensu stricto having the largest territorial extension, occupying ca. 70% of the biome (Felfili et al, 2013;Mota et al, 2014). This pattern promotes a greater diversity of subtypes, as landscapes with typic dense and thin vegetation over deep soils and rocky landscapes with shallow soils and rocky outcrops conditioning the presence of bushes and arboreal vegetation (Ribeiro & Walter, 2008;Mota et al, 2014).…”

“…70% of the biome (Felfili et al, 2013;Mota et al, 2014). This pattern promotes a greater diversity of subtypes, as landscapes with typic dense and thin vegetation over deep soils and rocky landscapes with shallow soils and rocky outcrops conditioning the presence of bushes and arboreal vegetation (Ribeiro & Walter, 2008;Mota et al, 2014).…”

Vegetation structure of naturally occurring areas of mangaba Hancornia speciosa Gomes in the mid-north region of Brazil

“…These authors observed that the species was not highlighted by these parameters. Similar results were obtained by Marmontel et al (2014), who reported that the species reached IV value of only 3.27%; as well as in results described by Mota et al (2014) in phytosociological survey carried out in Biribiri State Park, in Diamantina municipality, State of Minas Gerais where the mangaba did not stood out among the other species, reaching IV value of only 1.23%. It should be pointed out that the presence of the species H. sucuuba with IV values between 18.18 and 29.59% may be indicative of suitable area of growing and conservation of mangaba, however other studies are needed to quantify the relationship between the two species.…”